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通过全流程系统取样,详细讨论了高端切割丝中夹杂物的生成规律。结果表明:Si-Mn脱氧与低碱度渣精炼时,软吹结束后夹杂物成分已集中分布于Mn O-Si O2-Al2O3或Ca O-Si O2-Al2O3三元系低熔点区。前者为内生夹杂物,后者为精炼渣卷入钢液乳化而造成的外来夹杂物。Mn O-Si O2-Al2O3系夹杂物中Si O2含量在连铸坯凝固时明显增加,导致Si O2析出形成双相复合夹杂物。热轧时二者由于变形性能的差别而逐渐发生相分离,最终在盘条中形成单独存在的Si O2夹杂物。此类高Si O2夹杂物在拉拔时将破碎而沿轧向成为不连续、细小点状夹杂物:切割丝连续拉拔至29 602 km时一直未发现高Si O2夹杂物导致的断丝。因此,高端切割丝中夹杂物的控制不必过分强调夹杂物低熔点化,而应着眼于全流程控制并实现最终夹杂物的细小化。
Through the whole process of sampling system, discussed in detail the formation of inclusions in high-end cutting wire. The results show that the composition of inclusions in Si-Mn deoxidation and low-basicity slag refining is concentrated in the low melting point region of Mn O-Si O2-Al2O3 or Ca O-Si O2-Al2O3 after soft blowing. The former is endogenous inclusions, which are foreign inclusions caused by the involvement of refining slag in the molten steel. The content of Si O2 in Mn O-Si O2-Al2O3 inclusions increased significantly during the solidification of the slab, resulting in the precipitation of Si O2 into two-phase composite inclusions. During hot rolling, the phase separation occurs gradually due to the difference of the deformation properties, and finally the single existence of Si O2 inclusions is formed in the wire rod. Such high-Si O2 inclusions will be broken during drawing and become discontinuous along the rolling direction. The fine spot-like inclusions: no broken wire due to high Si O2 inclusions has been found when the cutting wire is continuously drawn to 29 602 km. Therefore, the control of inclusions in high-end cutting wire need not be too much emphasis on inclusions melting point, but should focus on the whole process control and achieve the final inclusions of the fine.